Genetic and phenotypic analysis of the mouse mutant mh 2J , an Ap3d allele caused by IAP element insertion

Kantheti, Prameela; Díaz, María Alejandra; Peden, Andrew A.; Seong, Eunju; Dolan, David F.; Robinson, Margaret S.; Noebels, Jeffrey L.; Burmeister, Margit

doi:10.1007/s00335-002-2238-8

Cited by 31 publications

(51 citation statements)

References 33 publications

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“…Moreover, whether we analyzed the ZnT3 levels in SV derived from mocha or in the AP-3 hypomorph allele mocha 2J, we detect a similar reduction (our unpublished observations). These results are striking because in mocha 2J, ZnT3 levels are reduced in neocortex but not in hippocampus (Kantheti et al, 2003), suggesting that cells that possess normal ZnT3 levels do not target the transporter to SV. The identification of new SV proteins enriched in AP-3-derived synaptic vesicles will help us to clarify the role that the absence of AP-3 possess on the fate of membrane protein at the synapse or elsewhere in the neuron.…”

Section: Discussionmentioning

confidence: 93%

“…We believe the decrease is likely mostly synaptic because the majority of the ZnT3 immunoreactivity in brain is synaptic and little is observed in cell bodies (Wenzel et al, 1997;our unpublished observations). In fact, the low levels of ZnT3 immunoreactivity remain in the cell bodies of AP-3 Ϫ/Ϫ mouse brain neurons (Kantheti et al, 1998(Kantheti et al, , 2003, suggesting that the reduction in the ZnT3 levels is likely a post-Golgi effect. Moreover, whether we analyzed the ZnT3 levels in SV derived from mocha or in the AP-3 hypomorph allele mocha 2J, we detect a similar reduction (our unpublished observations).…”

Section: Discussionmentioning

confidence: 99%

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The Zinc Transporter ZnT3 Interacts with AP-3 and It Is Preferentially Targeted to a Distinct Synaptic Vesicle Subpopulation

Salazar

Love

Werner

et al. 2004

MBoC

109

172

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Synaptic vesicles (SV) are generated by two different mechanisms, one AP-2 dependent and one AP-3 dependent. It has been uncertain, however, whether these mechanisms generate SV that differ in molecular composition. We explored this hypothesis by analyzing the targeting of ZnT3 and synaptophysin both to PC12 synaptic-like microvesicles (SLMV) as well as SV isolated from wild-type and AP-3-deficient mocha brains. ZnT3 cytosolic tail interacted selectively with AP-3 in cell-free assays. Accordingly, pharmacological disruption of either AP-2-or AP-3-dependent SLMV biogenesis preferentially reduced synaptophysin or ZnT3 targeting, respectively; suggesting that these antigens were concentrated in different vesicles. As predicted, immuno-isolated SLMV revealed that ZnT3 and synaptophysin were enriched in different vesicle populations. Likewise, morphological and biochemical analyses in hippocampal neurons indicated that these two antigens were also present in distinct but overlapping domains. ZnT3 SV content was reduced in AP-3-deficient neurons, but synaptophysin was not altered in the AP-3 null background. Our evidence indicates that neuroendocrine cells assemble molecularly heterogeneous SV and suggests that this diversity could contribute to the functional variety of synapses. INTRODUCTIONThe molecular diversity in total brain synaptic vesicle (SV) composition is generally presumed to result from differential expression of synaptic vesicle membrane proteins in different brain regions. However, the possibility that synaptic vesicles differ in composition because of different biogenesis mechanisms has not been explored. Different vesiculation pathways could result in molecularly diverse synaptic vesicles. Vesiculation mechanisms are known to produce distinct cargo carriers from a population of donor membranes (Bonifacino and Dell'Angelica, 1999;Springer et al., 1999;Boehm and Bonifacino, 2001). This process is achieved by adaptor complexes that recognize and concentrate specific membrane proteins in the donor membranes (Bonifacino and Dell 'Angelica, 1999;Kirchhausen, 1999). PC12 cells have been shown to possess two such adaptor-dependent pathways for the assembly of synaptic vesicles, also known as synaptic-like microvesicles (SLMV) (Shi et al., 1998;de Wit et al., 1999;Jarousse and Kelly, 2001). In one pathway, SLMV are generated from the plasma membrane by a vesiculation mechanism that requires the adaptor AP-2, clathrin, and the GTPase dynamin (Shi et al., 1998). In the second pathway, SLMV are generated from endosomes by the adaptor complex AP-3 (Faundez et al., 1998;Blumstein et al., 2001) and the GTPase ARF1 (Faundez et al., 1997). In contrast to the plasma membrane pathway, the endosomederived mechanism is highly sensitive to brefeldin A (BFA) (Shi et al., 1998).Phenotypes observed in the AP-3-deficient mocha mouse are consistent with a role for the AP-3-dependent, endosome-derived pathway in neurons (Kantheti et al., 1998). The mocha mossy fibers are devoid of both the synaptic vesiclespecific zinc transpor...

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

The Zinc Transporter ZnT3 Interacts with AP-3 and It Is Preferentially Targeted to a Distinct Synaptic Vesicle Subpopulation

Salazar

Love

Werner

et al. 2004

MBoC

109

172

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“…Fortunately, aspects of AP-3 function have been revealed by the AP-3 mouse mutants mocha (Kantheti et al, 1998;Kantheti et al, 2003) and pearl (Feng et al, 1999). Both mocha and pearl fail to assemble functional AP-3 complexes, and this defect is associated with impaired biogenesis of lysosomes and specialized secretory organelles, such as melanosomes, platelet-dense granules, lymphocyte cytotoxic granules, neutrophil granules (Dell'Angelica et al, 2000;Benson et al, 2003;Clark et al, 2003), and synaptic vesicle subpopulations (Kantheti et al, 1998(Kantheti et al, , 2003Nakatsu et al, 2004; Salazar et al, 2004a,b;Seong et al, 2005). In humans, genetic deficiencies in AP-3 function trigger the Hermansky-Pudlak type II syndrome; a disease that, like AP-3-deficiency in mice, is characterized by defective assembly of lysosome/lysosome-related organelles, pigment dilution, and bleeding disorders (Dell'Angelica et al, 1999;Clark et al, 2003).…”

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confidence: 99%

Phosphatidylinositol-4-Kinase Type II α Is a Component of Adaptor Protein-3-derived Vesicles

Salazar

Craige

Wainer

et al. 2005

MBoC

136

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A membrane fraction enriched in vesicles containing the adaptor protein (AP) -3 cargo zinc transporter 3 was generated from PC12 cells and was used to identify new components of these organelles by mass spectrometry. Proteins prominently represented in the fraction included AP-3 subunits, synaptic vesicle proteins, and lysosomal proteins known to be sorted in an AP-3-dependent way or to interact genetically with AP-3. A protein enriched in this fraction was phosphatidylinositol-4-kinase type II␣ (PI4KII␣). Biochemical, pharmacological, and morphological analyses supported the presence of PI4KII␣ in AP-3-positive organelles. Furthermore, the subcellular localization of PI4KII␣ was altered in cells from AP-3-deficient mocha mutant mice. The PI4KII␣ normally present both in perinuclear and peripheral organelles was substantially decreased in the peripheral membranes of AP-3-deficient mocha fibroblasts. In addition, as is the case for other proteins sorted in an AP-3-dependent way, PI4KII␣ content was strongly reduced in nerve terminals of mocha hippocampal mossy fibers. The functional relationship between AP-3 and PI4KII␣ was further explored by PI4KII␣ knockdown experiments. Reduction of the cellular content of PI4KII␣ strongly decreased the punctate distribution of AP-3 observed in PC12 cells. These results indicate that PI4KII␣ is present on AP-3 organelles where it regulates AP-3 function. INTRODUCTIONMembrane-enclosed organelles possess distinctive protein compositions that are dynamically maintained by inbound and outbound vesicle carriers. These vesicles selectively concentrate appropriate membrane proteins while leaving behind resident proteins found in the donor organelle, a process called sorting (Bonifacino and Glick, 2004). Central to membrane protein sorting and vesiculation are a family of cytosolic coat complexes that mediate vesicle budding and function as cargo-specific adaptors. These include monomeric proteins and the heterotetrameric adaptor proteins (AP)-1, -2, -3, and -4 (Bonifacino and Glick, 2004;Robinson, 2004). These coats participate in the generation of vesicles that carry a unique array of membrane protein "cargoes." The characterization of these carriers has played a major role in the functional dissection of coat-dependent sorting and vesiculation mechanisms. For example, vesicles "in a basket" isolated from brain led to the biochemical identification of the first sorting machinery, clathrin and the AP-1 and AP-2 adaptors (Kanaseki and Kadota, 1969;Pearse, 1975;Pfeffer and Kelly, 1981;Pearse and Crowther, 1987). Subsequent studies of cargo molecules in brain clathrin-coated vesicles were crucial in revealing mechanisms of synaptic vesicle recycling (Pfeffer and Kelly, 1985;Maycox et al., 1992;Blondeau et al., 2004). The advent of complete genome sequencing and the concomitant development of informatics tools has led to the rapid identification of proteins by mass spectrometry (Taylor et al., 2003). Application of these methodologies to clathrin-coated vesicles has allowed the identifi...

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“…The adaptor complex AP-3 is involved in the biogenesis of lysosomes, lysosome-related organelles and synaptic vesicles (10,11). AP-3-deficient mouse models mocha and mocha2J develop a complex neurological phenotype that at the cellular level is characterized by the lack of intravesicular synaptic vesicle ionic zinc (7,8). Vesicles are devoid of zinc because the synaptic vesicle-specific zinc transporter 3 (ZnT3) does not reach a specialized population of synaptic vesicles (7)(8)(9).…”

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confidence: 99%

“…AP-3-deficient mouse models mocha and mocha2J develop a complex neurological phenotype that at the cellular level is characterized by the lack of intravesicular synaptic vesicle ionic zinc (7,8). Vesicles are devoid of zinc because the synaptic vesicle-specific zinc transporter 3 (ZnT3) does not reach a specialized population of synaptic vesicles (7)(8)(9). The defective sorting of ZnT3 to mocha synaptic vesicles most probably occurs because ZnT3 possesses cytosolic determinants robustly recognized by the adaptor complex AP-3 (9).…”

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confidence: 99%

AP-3-dependent Mechanisms Control the Targeting of a Chloride Channel (ClC-3) in Neuronal and Non-neuronal Cells

Salazar¹,

Love²,

Styers³

et al. 2004

Journal of Biological Chemistry

Self Cite

108

130

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Adaptor protein (AP)-2 and AP-3-dependent mechanisms control the sorting of membrane proteins into synaptic vesicles. Mouse models deficient in AP-3, mocha, develop a neurological phenotype of which the central feature is an alteration of the luminal synaptic vesicle composition. This is caused by a severe reduction of vesicular levels of the zinc transporter 3 (ZnT3). It is presently unknown whether this mocha defect is restricted to ZnT3 or encompasses other synaptic vesicle proteins capable of modifying synaptic vesicle contents, such as transporters or channels. In this study, we identified a chloride channel, ClC-3, whose level in synaptic vesicles and hippocampal mossy fiber terminals was reduced in the context of the mocha AP-3 deficiency. In PC-12 cells, ClC-3 was present in transferrin receptorpositive endosomes, where it was targeted to synapticlike microvesicles (SLMV) by a mechanism sensitive to brefeldin A, a signature of the AP-3-dependent route of SLMV biogenesis. ClC-3 was packed in SLMV along with the AP-3-targeted synaptic vesicle protein ZnT3. Co-segregation of ClC-3 and ZnT3 to common intracellular compartments was functionally significant as revealed by increased vesicular zinc transport with increased ClC3 expression. Our work has identified a synaptic vesicle protein in which trafficking to synaptic vesicles is regulated by AP-3. In addition, our findings indicate that ClC-3 and ZnT3 reside in a common vesicle population where they functionally interact to determine vesicle luminal composition.

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Genetic and phenotypic analysis of the mouse mutant mh 2J , an Ap3d allele caused by IAP element insertion

Cited by 31 publications

References 33 publications

The Zinc Transporter ZnT3 Interacts with AP-3 and It Is Preferentially Targeted to a Distinct Synaptic Vesicle Subpopulation

The Zinc Transporter ZnT3 Interacts with AP-3 and It Is Preferentially Targeted to a Distinct Synaptic Vesicle Subpopulation

Phosphatidylinositol-4-Kinase Type II α Is a Component of Adaptor Protein-3-derived Vesicles

AP-3-dependent Mechanisms Control the Targeting of a Chloride Channel (ClC-3) in Neuronal and Non-neuronal Cells

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